A Scheduled Ancient Monument is defined in the Ancient Monuments and Archaeological Areas Act 1979 and the National Heritage Act 1983 of the United Kingdom government.

The Secretary of State for National Heritage keeps a register of nationally important sites. In practice, the implementation of the legislation is delegated to the government bodies English Heritage in England, Cadw in Wales, Historic Scotland in Scotland, and the Environment and Heritage Service in Northern Ireland.

A long list of criteria is used to decide whether an Ancient Monument should become a Scheduled Ancient Monument. Scheduling affords greater protection as it becomes illegal to in any way tamper with a designated area.

However, protection can also be given by taking the monument under ownership or guardianship, or by designating the location as an Area of Archaeological Importance. As of 2004 only five city centres, all in England, have been designated AAIs (Canterbury, Chester, Exeter, Hereford and York).

Often Ancient Monuments are also Grade I or Grade II Listed buildings, or they are situated in a Conservation Area.

The Scheduling system is criticised by some as being cumbersome. Until recently it had a limited definition of what constitutes a monument and ritual landscapes, flint scatters or underwater sites were difficult to Schedule.

Example 1: Wymondham Abbey in Norfolk is a Scheduled Ancient Monument, a Grade I Listed Building, and lies in Wymondham Conservation Area.

Example 2: Paston Great Barn, also in Norfolk, is a Scheduled Ancient Monument and a Grade II Listed Building. Because of the presence of rare bats, it is also on a Site of Special Scientific Interest (SSSI) and a candidate for Special Area of Conservation (cSAC) European Union protective status.

See also:

• Berney Arms
• Derwent Valley Mills
• Six Hills
• Winchester Palace
• Portslade Manor